Technical Questions

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Advantages of low-density aggregate

Q. What are the advantages of low-density aggregate?


A. Low-density aggregate is used to produce concrete with low density. It has many and varied applications: multistory building frames and floors, curtain walls, shell roofs, folded plates, bridges, prestressed or precast elements of all types including marine structures, and other applications where large reductions in dead load are desired (ACI 213R). In addition, the low-density aggregates provide thermal insulation, internal curing (absorbed water may be released for hydration during curing), and better compatibility between the paste and the aggregate (lower elastic modulus of the aggregate). There are also low-density, nonstructural concretes having an oven-dry density of 800 kg/m3 (50 lb/ft3) or less. These concretes achieve their low density by incorporating low-density aggregates, air entrainment, or preformed foam. These concretes are most commonly used in roof deck systems, where the advantages include insulating value and improved fire resistance (ACI 523.1R, ACI 523.2R).


References: SP-1(02); E-1(16); ACI 221R-96; ACI 213R-14; ACI 523.1R; ACI 523.2R

Topics in Concrete: Aggregate; Concrete Fundamentals; Materials; Lightweight

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